1. Field of the Invention
This invention generally relates to a bicycle control device. More specifically, the present invention relates to a bicycle shift control device that performs shifting operations including a winding operation without a lost motion occurring during movement of a winding lever.
2. Background Information
Bicycling is becoming an increasingly more popular form of recreation as well as a means of transportation. Moreover, bicycling has become a very popular competitive sport for both amateurs and professionals. Whether the bicycle is used for recreation, transportation or competition, the bicycle industry is constantly improving the various components of the bicycle. In particular, control devices for shifting have been extensively redesigned in recent years.
Currently, there are many types of cable operated shifting devices currently being installed on bicycles. For example, some cable operated shifting devices have a pair of shift levers and a cable winding mechanism that rotates via a ratchet mechanism. With conventional cable operated shifting devices of this type, operation of one of the shift lever causes the cable winder to rotate via the ratchet mechanism in one direction by one gear at a time. As a result, the cable is wound around the cable winder, and a shift is made by the shift mechanism from one gear to the next gear. Operation of the other shift lever causes the ratchet mechanism to be released and the cable winder to rotate in the other direction by one gear at a time. As a result, the cable that was wound on the cable winder is played out, and a shift is made in the opposite direction by the shift mechanism. More recently, some cable operated shifting devices have been developed that allow multiple gear shifts in a single operation of one of the shift levers. These prior shifting devices can be complicated and expensive to manufacture and assemble. Furthermore, these prior shifting devices are sometimes heavy and/or cumbersome.
Also in some of these prior shifting devices, a winding pawl is used to rotate a wire takeup member by engaging a set of winding ratchet teeth of a ratchet wheel that is mounted to the wire takeup member. The winding pawl is engaged with one of the winding ratchet tooth in a rest position. In some of these prior shifting devices, when a rider moves the winding lever, the winding pawl immediately rotates the wire takeup member which integrally rotates with the ratchet wheel. However, in other prior shifting devices, the winding pawl is disengaged from the winding ratchet teeth in a rest position. In this case, some amount of movement of the winding lever is required before the wire takeup member begins to rotate. In other words, some of prior shifting devices have some lost motion occurring in the winding lever.
In the shifting devices without lost motion, positioning teeth for holding the wire takeup member are formed on the same plate or at least they move integrally with the winding ratchet teeth. Thus, when one of the positioning teeth is caught (positioned) by a positioning pawl, the positions of the winding ratchet teeth are automatically fixed. Therefore, in these shifting devices without lost motion, it is theoretically possible to design the rest position of the winding pawl to be at the bottom of the winding teeth. If this type of design is created, there is no lost motion, that is, when the winding lever is rotated, the wire takeup member is immediately rotated by the winding pawl. However, in a mass production, it is not easy to precisely position the winding pawl relative to the positioning pawl(s) and the ratchet wheel and so on. Therefore, some manual adjustment would be necessary in order to assembly a shifting device having such a design. This type of shifting device can be very time consuming to assemble, and thus, increase the manufacture costs of the shifting device.
In view of the above, it will be apparent to those skilled in the art from this disclosure that there exists a need for an improved bicycle control (shifting) device. This invention addresses this need in the art as well as other needs, which will become apparent to those skilled in the art from this disclosure.